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<pre><span class="sourceLineNo">001</span><a name="line.1"></a>
<span class="sourceLineNo">002</span>/*<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2014 Archie L. Cobbs. All rights reserved.<a name="line.3"></a>
<span class="sourceLineNo">004</span> *<a name="line.4"></a>
<span class="sourceLineNo">005</span> * $Id: UnaryExprParser.html 842 2015-03-07 18:20:42Z archie.cobbs $<a name="line.5"></a>
<span class="sourceLineNo">006</span> */<a name="line.6"></a>
<span class="sourceLineNo">007</span><a name="line.7"></a>
<span class="sourceLineNo">008</span>package org.jsimpledb.parse.expr;<a name="line.8"></a>
<span class="sourceLineNo">009</span><a name="line.9"></a>
<span class="sourceLineNo">010</span>import java.util.regex.Matcher;<a name="line.10"></a>
<span class="sourceLineNo">011</span><a name="line.11"></a>
<span class="sourceLineNo">012</span>import org.jsimpledb.parse.ParseContext;<a name="line.12"></a>
<span class="sourceLineNo">013</span>import org.jsimpledb.parse.ParseSession;<a name="line.13"></a>
<span class="sourceLineNo">014</span>import org.jsimpledb.parse.Parser;<a name="line.14"></a>
<span class="sourceLineNo">015</span>import org.jsimpledb.parse.SpaceParser;<a name="line.15"></a>
<span class="sourceLineNo">016</span><a name="line.16"></a>
<span class="sourceLineNo">017</span>/**<a name="line.17"></a>
<span class="sourceLineNo">018</span> * Parses unary expressions using one of {@code !}, {@code ~}, {@code +}, {@code -}, {@code ++}, {@code --}.<a name="line.18"></a>
<span class="sourceLineNo">019</span> */<a name="line.19"></a>
<span class="sourceLineNo">020</span>public class UnaryExprParser implements Parser&lt;Node&gt; {<a name="line.20"></a>
<span class="sourceLineNo">021</span><a name="line.21"></a>
<span class="sourceLineNo">022</span>    public static final UnaryExprParser INSTANCE = new UnaryExprParser();<a name="line.22"></a>
<span class="sourceLineNo">023</span><a name="line.23"></a>
<span class="sourceLineNo">024</span>    private final SpaceParser spaceParser = new SpaceParser();<a name="line.24"></a>
<span class="sourceLineNo">025</span><a name="line.25"></a>
<span class="sourceLineNo">026</span>    @Override<a name="line.26"></a>
<span class="sourceLineNo">027</span>    public Node parse(ParseSession session, ParseContext ctx, boolean complete) {<a name="line.27"></a>
<span class="sourceLineNo">028</span><a name="line.28"></a>
<span class="sourceLineNo">029</span>        // Parse operator, if any<a name="line.29"></a>
<span class="sourceLineNo">030</span>        final Matcher matcher = ctx.tryPattern("\\+{1,2}|-{1,2}|!|~");<a name="line.30"></a>
<span class="sourceLineNo">031</span>        if (matcher == null)<a name="line.31"></a>
<span class="sourceLineNo">032</span>            return BaseExprParser.INSTANCE.parse(session, ctx, complete);<a name="line.32"></a>
<span class="sourceLineNo">033</span>        final String opsym = matcher.group();<a name="line.33"></a>
<span class="sourceLineNo">034</span>        this.spaceParser.parse(ctx, complete);<a name="line.34"></a>
<span class="sourceLineNo">035</span><a name="line.35"></a>
<span class="sourceLineNo">036</span>        // Parse argument (this recursion will give the correct right-to-left association)<a name="line.36"></a>
<span class="sourceLineNo">037</span>        final Node arg = this.parse(session, ctx, complete);<a name="line.37"></a>
<span class="sourceLineNo">038</span><a name="line.38"></a>
<span class="sourceLineNo">039</span>        // Proceed with parse<a name="line.39"></a>
<span class="sourceLineNo">040</span>        switch (opsym) {<a name="line.40"></a>
<span class="sourceLineNo">041</span>        case "!":<a name="line.41"></a>
<span class="sourceLineNo">042</span>            return this.createUnaryOpNode(Op.LOGICAL_NOT, arg);<a name="line.42"></a>
<span class="sourceLineNo">043</span>        case "~":<a name="line.43"></a>
<span class="sourceLineNo">044</span>            return this.createUnaryOpNode(Op.INVERT, arg);<a name="line.44"></a>
<span class="sourceLineNo">045</span>        case "+":<a name="line.45"></a>
<span class="sourceLineNo">046</span>            return this.createUnaryOpNode(Op.UNARY_PLUS, arg);<a name="line.46"></a>
<span class="sourceLineNo">047</span>        case "-":<a name="line.47"></a>
<span class="sourceLineNo">048</span>            return this.createUnaryOpNode(Op.UNARY_MINUS, arg);<a name="line.48"></a>
<span class="sourceLineNo">049</span>        case "++":<a name="line.49"></a>
<span class="sourceLineNo">050</span>            return this.createPrecrementNode("increment", arg, true);<a name="line.50"></a>
<span class="sourceLineNo">051</span>        case "--":<a name="line.51"></a>
<span class="sourceLineNo">052</span>            return this.createPrecrementNode("decrement", arg, false);<a name="line.52"></a>
<span class="sourceLineNo">053</span>        default:<a name="line.53"></a>
<span class="sourceLineNo">054</span>            throw new RuntimeException("internal error: " + opsym);<a name="line.54"></a>
<span class="sourceLineNo">055</span>        }<a name="line.55"></a>
<span class="sourceLineNo">056</span>    }<a name="line.56"></a>
<span class="sourceLineNo">057</span><a name="line.57"></a>
<span class="sourceLineNo">058</span>    private Node createUnaryOpNode(final Op op, final Node arg) {<a name="line.58"></a>
<span class="sourceLineNo">059</span>        return new Node() {<a name="line.59"></a>
<span class="sourceLineNo">060</span>            @Override<a name="line.60"></a>
<span class="sourceLineNo">061</span>            public Value evaluate(ParseSession session) {<a name="line.61"></a>
<span class="sourceLineNo">062</span>                return op.apply(session, arg.evaluate(session));<a name="line.62"></a>
<span class="sourceLineNo">063</span>            }<a name="line.63"></a>
<span class="sourceLineNo">064</span>        };<a name="line.64"></a>
<span class="sourceLineNo">065</span>    }<a name="line.65"></a>
<span class="sourceLineNo">066</span><a name="line.66"></a>
<span class="sourceLineNo">067</span>    private Node createPrecrementNode(final String operation, final Node node, final boolean increment) {<a name="line.67"></a>
<span class="sourceLineNo">068</span>        return new Node() {<a name="line.68"></a>
<span class="sourceLineNo">069</span>            @Override<a name="line.69"></a>
<span class="sourceLineNo">070</span>            public Value evaluate(ParseSession session) {<a name="line.70"></a>
<span class="sourceLineNo">071</span>                return node.evaluate(session).xxcrement(session, "pre-" + operation, increment);<a name="line.71"></a>
<span class="sourceLineNo">072</span>            }<a name="line.72"></a>
<span class="sourceLineNo">073</span>        };<a name="line.73"></a>
<span class="sourceLineNo">074</span>    }<a name="line.74"></a>
<span class="sourceLineNo">075</span>}<a name="line.75"></a>
<span class="sourceLineNo">076</span><a name="line.76"></a>




























































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